1. Field of the Invention
The present invention relates to a method for controlling the supply voltage for an integrated circuit, which is connected to a voltage regulation module. Further, the present invention relates to an apparatus with a voltage regulation module and an integrated circuit.
2. Description of the Related Art
A voltage regulator module is provided to supply one or more integrated circuits with a varying voltage. In particular, the voltage regulator module is provided to supply a microprocessor with voltage. The voltage regulator module is further provided to vary the voltage for the integrated circuit. Different operation modes of the integrated circuit require various voltages. The voltage regulator module is formed as a single semiconductor chip. The integrated circuit is also formed as a single semiconductor chip. Usually, the voltage regulator module and the integrated circuit are on the same board.
A known example for the integrated circuit 20 with the voltage regulator module 10 is shown in FIG. 5. The voltage regulation module 10 is formed as a single semiconductor chip. The integrated circuit 20 is also formed as a single semiconductor chip. The voltage regulation module 10 comprises an operational amplifier 12 and a voltage source 14. The operational amplifier 12 provides the supply voltage Vdd for the integrated circuit 20.
The integrated circuit 20 comprises the voltage mesh 22. The voltage mesh 22 receives the supply voltage Vdd and provides a plurality of different voltages on the integrated circuit 20. The voltage mesh 22 is directly connected to the negative input terminal of the operation amplifier 12 via a sense line 18. The sense line 18 acts as a feedback line from the integrated circuit 20 to the voltage regulator module 10 in order to keep the voltage stable on the integrated circuit 20.
The changing of the voltage on the integrated circuit 20 should be done as fast as possible.
In addition, in order to vary the voltage, it is advantageous to track both cycle time and voltage on the integrated circuit 20 with respect to the workload. The variation of the cycle time is performed by an additional component, e.g. serial data port of an I2C (Inter-Integrated Circuit) bus, not shown in FIG. 5.
Conventional voltage regulator modules are programmed by buses having a bandwidth of about 1 kbit/s to 100 kbit/s. For example, the voltage regulator modules are programmed by an I2C bus or an SMBus (System Management Bus). The I2C bus is operating at a frequency of about 1 MHz. This is relative relatively slow compared with the microprocessor or other integrated circuits.
To set new voltages about 20 bits are used. Thus, there are required about 20 μs to 200 μs in order to program new voltages on the voltage regulator module 10. Compared to the cycle time of a typical microprocessor about 60,000 cycles occur on the chip until the new voltage is set at the voltage regulator module 10.